Electronic Flora of South Australia Species Fact Sheet
Phylum Rhodophyta – Class Florideophyceae – Order Hildenbrandiales – Family Hildenbrandiaceae
Selected citations: Askenasy 1888: 31, pl. 2 figs 11–14. Chapman & Parkinson 1974: 164, fig. 51. Denizot 1968: 200, fig. p. 197. Ricker 1987: 186, fig. 78.
Thallus (Fig. 43A)dark red-brown to purplish, several cm across, marginally thin but becoming 0.5–1 mm thick and developing profuse surface verrucose to tuberculate excrescences to a total thickness of 3–6 mm, the crust tightly adherent when young but older parts readily separable from the rock substratum. Structure (Figs 42C, 43B). Basal layer of irregularly radiating rows of cells, 3–5 µm in diameter and L/D 1–2, producing erect filaments which in older parts differentiate to a medulla of subspherical to polygonal cells, irregularly arranged or in vague rows (in older parts with areas of rows of cells separating slightly), 6–10 µm in diameter, with a cortex of erect, simple, filaments, laterally closely coherent, of small, cuboidal to slightly ovoid cells 3–4 µm in diameter and L/D 1–1.5. Rhodoplasts minute, a few per cell.
Reproduction: Conceptacles (Figs 42C, 43C) subspherical to ovoid, 100–160 µm in diameter and 100–200 (–250) µm long, with an ostiole 15–25 µm across; tetrasporangia 8–10 (–12) pin in diameter and 25–30 (–40) µm long, zonately to irregularly divided with transverse to oblique cross walls, old walls usually remaining; paraphyses plentiful, 15–20 µm and 3–5 (–7) cells long, 3–4 mm in diameter.
Type from Orange Bay, Fuegia; in PC.
In southern Australia, recorded only from Cape Willoughby, Kangaroo I., S. Aust., in a high-level rock pool, S side of Cape (Womersley, 25.i.1948; AD, A7018, and 8.i.1950; AD, Al2986).
Taxonomic notes: The above specimens agree well with this subantarctic species which differs from others in its distinctive tuberculate form. It may occur on SE Tasmanian coasts but has been overlooked.
ASKENASY, E. (1888). Algen. In Engler, A. (Ed.), Die Forschungsreise S.M.S. Gazelle in den Jahren 1874 bis 1876. IV Th. Bot., pp. 1–58, Plates 1–12. (Mittler: Berlin.)
CHAPMAN, V.J. & PARKINSON, P.G. (1974). The marine algae of New Zealand. Part DI: Rhodophyceae. Issue 3: Cryptonemiales. (Cramer: Germany.)
DENIZOT, M. (1968). Les Algues Floridées encroûtantes (a l'exclusion des Corallinacées). (Paris.)
HARIOT, P. (1887). Algues Magellaniques nouvelles. J. de Bot. 1, 55–59, 72–74.
RICKER, R.W. (1987). Taxonomy and biogeography of Macquarie Island Seaweeds. [British Museum (N.H.): London.]
The Marine Benthic Flora of Southern Australia Part IIIA complete list of references.
Womersley, H.B.S. (14 January, 1994)
The Marine Benthic Flora of Southern Australia
Rhodophyta. Part IIIA, Bangiophyceae and Florideophyceae (to Gigartinales)
Reproduced with permission from The Marine Benthic Flora of Southern Australia Part IIIA 1994, by H.B.S. Womersley. Australian Biological Resources Study, Canberra. Copyright Commonwealth of Australia.
Illustrations in Womersley Part IIIA, 1994: FIGS 42C, 43 A–C.
Figure 42 enlarge
Fig. 42. A. Hildenbrandia rubra (AD, A60783). Cross section of thallus with a conceptacle and irregularly divided tetrasporangia. B. Hildenbrandia crouanii (AD, Al2966). Cross section of thallus with a conceptacle with tetrasporangia divided by obliquely zonate walls. C. Hildenbrandia lecannellieri (AD, Al2986). Cross section of thallus and conceptacle (in part) with zonately and irregularly divided tetrasporangia. D. Hildenbrandia expansa (AD, A60088). Cross section of thallus and conceptacle (in part) showing regular horizontal and vertical rows of cells, with horizontal layers of larger cells (arrows), and zonately divided tetrasporangia with paraphyses. E–H. Rhodopeltis australis (E, AD, A15518; F, AD, A8320; G, AD, A34997; H, AD, A38735). E. Section of female nemathecium with a carpogonial branch and an auxiliary cell branch among paraphyses. F. Section of a female nemathecium with a carposporophyte borne on an auxiliary cell. G. Section of a male nemathecium with spermatangial branches. H. Section of outer cortex (with inner stellate cells) with tetrasporangia among short paraphyses.
Figure 43 enlarge
Fig. 43. A–C. Hildenbrandia lecannellieri (AD, Al2986). A. Thallus, showing surface with verrucose to tuberculate excrescences. B. Cross section of thallus with an area (darker) of slightly separated rows of older cells. C. Cross section of thallus with conceptacles. D. Hildenbrandia expansa (AD, A60088). Cross section of thallus showing horizontal layers of cells and conceptacles.
State Herbarium of South Australia